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add-inter-tool-invocation ​

This skill adds Inter-Tool Invocation support to a PPTB tool — either the caller side (launch another tool and get data back), the callee side (declare a contract so another tool can launch this one), or both. It generates the pptb.config.json invocation contract, the code that reads prefill data or returns a result, and the caller-side launchTool() / findToolsByCapability() calls, so a tool can reuse another tool's capability (an entity picker, a FetchXML builder) instead of reimplementing it.

launchTool() returns a Promise that resolves with the callee's data when it calls returnData(), or null if the callee closes without returning anything — and only one callee can be active per caller at a time.

When to use it ​

  • "Let this tool launch the entity picker tool and get the selected record back."
  • "Make my tool discoverable as a FetchXML builder other tools can launch."
  • "Add an invocation contract to pptb.config.json."
  • "My tool needs to reuse another installed tool's picker instead of building its own."
  • Alongside add-agent-integration, since the invocation contract layer is shared between inter-tool invocation and MCP agent exposure.

Inputs ​

  • Whether the tool acts as a caller, a callee, or both.
  • For a callee: the capability tags to advertise (e.g. entity-picker, fetchxml, record-selector), the expected prefill input shape, and the return value shape.
  • For a caller: the target tool's npm package name (or a capability tag to discover it dynamically), any prefill data to pass, and whether to override the inherited Dataverse connection.

What it does ​

  1. For a callee, adds an invocation object to pptb.config.json with invocation.version (semantic version of the contract), invocation.capabilities (discoverable tags), invocation.prefill (expected input schema), and invocation.returnTopic (return value schema).
  2. Generates callee-side code that reads incoming data via getLaunchContext() and sends its result back with returnData().
  3. Adds pptb.config.json to the files array in package.json so capability discovery works once the tool is published — invocation contracts aren't discoverable otherwise.
  4. For a caller, generates a launchTool() call that passes the target tool's ID (its npm package name), optional prefill data, and any connection overrides.
  5. Where the caller should discover a tool dynamically rather than hardcode a dependency, generates a findToolsByCapability() call against the relevant capability tag.
  6. Adds handling for the caller side that treats a null Promise resolution as "the callee closed without returning data" — not an error.
  7. Guards against launching a second callee while one is already active, since only one callee can be active per caller at a time.
  8. Reminds the developer that pptb-validate checks the declared data shapes but does not enforce them at runtime, so callee code must still validate incoming getLaunchContext() data defensively.

Example ​

Callee contract added to pptb.config.json:

json
{
  "invocation": {
    "version": "1.0.0",
    "capabilities": ["entity-picker", "record-selector"],
    "prefill": { "entityName": "string", "filter": "string?" },
    "returnTopic": { "recordId": "string", "entityName": "string" }
  }
}

Caller code generated to launch it:

javascript
const result = await toolboxAPI.launchTool('@my-org/entity-picker', {
  prefill: { entityName: 'account' },
});

if (result === null) {
  // Callee window closed without calling returnData() — not an error.
  return;
}

console.log(result.recordId, result.entityName);

Checklist it enforces ​

  • [ ] pptb.config.json declares invocation.version, invocation.capabilities, invocation.prefill, and invocation.returnTopic for any tool acting as a callee.
  • [ ] pptb.config.json is included in the files array in package.json so capability discovery works after publishing.
  • [ ] Callers handle a null resolution from launchTool() (the callee closed without returning data).
  • [ ] Callers don't attempt to launch a second callee while one is already active.
  • [ ] Capability tags used with findToolsByCapability() match tags actually declared by target tools.